Bearing units of the type disclosed herein may suitably be utilized to support a leaf spring assembly on a vehicle chassis. The bearing unit includes a bearing pin which passes through a spring eye on a leaf spring and is coupled to a shackle which in turn is coupled to a mounting bracket on the chassis by another identical bearing unit. The installation and replacement of prior art bearing units is time-consuming and relatively complicated. A disadvantage of one such prior art bearing unit is that it must be assembled in the field in a step-by-step procedure and, during assembly, a mechanic will frequently lose some of the bearing unit parts. Substantial down-time is thus incurred. Accordingly, it is an object of the present invention to provide a preassembled bearing unit which is easy to install in the field.
Bearing units of the type disclosed herein bear a substantial load, and thus it is important that the maximum bearing surface be provided between moving parts and that lubricant always be provided between the relatively moving bearing surfaces.
When introducing lubricant to bearing units which pass lubricant axially out both axial ends thereof, many mechanics will unfortunately, upon observing lubricant pass out one axial end of the bearing unit, frequently assume that the lubrication is complete and terminate the lubricating process. Frequently, although the lubricant passes out one axial end of the bearing unit, it does not pass to the other axial end and thus if introduction of lubricant is interrupted when lubricant passes out one end only, a portion of the bearing surface may not be adequately lubricated. Any such non-lubricated bearing pin portion rapidly wears. Accordingly, it is another object of the present invention to provide a bearing unit which will pass lubricant from one closed end to and through an opposite end to aid mechanics in determining when adequate lubrication has been completed.
Still another object of the present invention is to provide a bearing unit which will minimize human error in lubricating.
Yet another object of the present invention is to provide a bearing unit which is preassembled and includes a sleeve that internally receives a spiral bushing and internally mounts bearing pin sealing units at axially opposite ends of the spiral bushing.
It is another object of the present invention to provide a bearing unit of the type described having a sleeve internally receiving a pair of sealing units at opposite ends thereof, at least one of the sealing units preventing lubricant from passing thereby and including a resilient sealing ring which is rectangular in cross section.
A further object of the present invention is to provide a bearing unit of the type described including a pair of axially spaced, resilient sealing rings which sealingly engage a bearing pin and retaining rings which axially restrict movement of the sealing rings and are radially spaced from the bearing pin.
A still further object of the present invention is to provide a bearing unit of the type described, including a bearing pin receiving shell, resilient annular seals mounted in the shell, and end rings carried by the sleeve which prevent the seals from moving axially outwardly.
Another object of the present invention is to provide a bearing unit of the type described which prevents lubricant from passing out one end thereof and, at the other end, permits lubricant to pass axially, but inhibits the axially inward passage of foreign matter.